1. Field of the Invention
The present invention relates to a measurement apparatus and a measurement method. Particularly, the present invention relates to a measurement apparatus and a measurement method that measure a current consumed by an electronic device.
2. Related Art
A test apparatus has a function to measure a consumption current when a device under test is in resting state, for example, as disclosed in a non-patent document 1: Yushihiro Hashimoto and Kenji Izawa “Increase speed twentyfold Advantest LSI tester, Nikkei Electronics published by Nikkei Business Publications, Inc on Jul. 7, 1997, P85; a non-patent document2: Nobuhiro Sato, Yoshihiro Hashimoto , “A High Precision Iddg Measurement System with Improve Dynamic Load Regulation”, USA, ITC2003, 2003, P 410 Paper 15, 2; a non-patent document 3 : Rachit Rajsman, “Iddg Testing For CMOS VLSI”, USA, Artech House INC., 1995 , P141 Chapter 5. The test apparatus uses an amplifier being capable of outputting a large current as an amplifier for the power supply of the device under test. However, if such amplifier being capable of outputting a large current, the consumption current by the device under test in resting state can not be accurately measured. Therefore, the test apparatus has accurately measured the current in resting state by separately providing an amplifier of which current supply performance is not good but which can accurately measure the current and changing it to another amplifier for testing a current in resting state when the current is measured in resting state.
Meanwhile, the test apparatus includes a switch for a large current that can apply a large current when the device under test is in operation in order to switch the amplifier that provides a power supply voltage between an operating state and a resting state of the device under test. However, the operating speed of the switch for a large current is slow. Therefore, it takes a long time to stabilize a current supply when the device under test is switched between the operating state and the resting state, so that the start of a measurement has gotten late.
Thus, the advantage of the present invention is to provide a measurement apparatus and a measurement method which are capable of solving the problem accompanying the conventional art. The above and other advantages can be achieved by combining the features recited in independent claims. Then, dependent claims define further effective specific example of the present invention.